Sound-damping mechanism



Sept. 2'5', 1923. 1,469,141

' A. EMETT SOUND DAMPING MECHAISM Filed Feb. 1o. 1922 2 sheets-sheet 1 Q4 A. I 2

Sept. 25, 1923.

A. EMETT soUND DAMHNG MEGHANISM FiledFeb. 1o, 1922 f '2 shuts-sheet 2 Patented Sept. 25, 1923.

ARTHUR EMETT, OF BIRMINGHAM, ENGLAND.

SOUND-D AMPING MECHANISB'I.

Application filed February 10, 1922. Serial No. 535,535.

T all whom it may concern.'

Be it known that I, ARTHUR EMETT, subject of the King of Great Britain, residing at 24; Tennyson Road, Small Heath, Birminghani` England, manufacturer, have invented certain new and useful Improvements in Sound-Damping Mechanism, of which the `following is a specification.

yThe invention provides the hereinafter described improvements in or connected with sound reproducing instruments such as gramophones.

According to the invention an air sack isused within a tubular passage beyond the sound box to be hand operated for controlling the effective size of the passage to change the volume and inellowness of the tone ot' the instrument at the will of the hearer. Said airsack is preferably an inflatable one normally contracted inthe passage and inflated to reduce the effective area ot said passage, but it may be an air sack normally inflated and capable of deflation for the purpose of controlling the effective size aforesaid. Said air sack is of indiarubber or other nonmetallic material, or substantially of such material, for mellowing the tone.

The desirable,construction of air sack is one which by inflation expands from the sides ot the passage to the center` and which can conveniently be constructed by two tubelike portions arranged the one within the other and air sealed at their ends the outer one to substantially fit the passage and the inner portion to expand. In particular the invention provides as a unit applicable to any existing instrument, an appliance comprising, an air sack as atoresaid,`an infla tion bulb, and a length of tubing connectingl the bulb with the air sack, all of' indiarubber or othernon-metallic flexible material quite flexible and with the air sack conformable to the passage; the bulb torl Fig. 2 is an outer end elevation of the air sack.

Fig. 3 is a transverse section on the dotted lines C. D. Fig. l.

Fig. 4 is a section on the dotted lines A. B. Fig. l.

Fig. 5 is a similar section as Fig. 8 but showing the air sack when inflated and how the inner wall expands from the sides to the center in gussets.

Fig. 6 shows ya sectional elevation ot one way the unit may be applied to the tone arm oi' a sound reproducing instrument.

Figs. 7, 8 and 9 show in transverse section and in plan an arrangement for key operation of the inliating bulb.

The air sack a is formed of two tube-like portions a2, a3 formed of india-rubber or like material disposed the one within the other and air sealed at their ends except at (it where said sack is joined up to the air supply tube. The outer end is sealed b y doubling the material of the two tubes as at argwhile the free ends are vulcanized together as at a6. Between the two ends the two tube-like portions are free of each other, as shown at a?, providing a space into which air under pressure is forced through the india-rubber tube c from the inflation bulb l which may be either hand, key, or otherwise operated. Fig. 6 shows how the unit 'Fig l is applied to the tubular tone arm c of an instrument, being threaded through said tone ai'ni, for which purpose the tube may be detachable at c2 near the bulb d. The tube c is of any convenient length so that the bearer may sit comfortably in a chair a distance away from the instrument and control the tone in Volume or mellowness as he wills, thereby giving the instrument an additional interest inasmuch as the hearer can display personalA musical ability and skill. and obtain much more interesting effects than hitherto.

The air sack (1, lies closely within the tone arm fitting the interior and is normally deflated allowing the maximum sound aperture therethrough. By squeezing the bulb al the air sack is inated to further bind it to the bore ot` the passage in the tone arm and to force the inner tube a3 inwardly towards the centre to further close or throttle the passage and in practice the air sack represented expands towards the centre, as represented by Fig. 5. Dependent upon the pressure on the bulb Z the etfective passage further is closed and again opened.. Immediately the pressure oi air is relieved expanded portions retreat or move back to normal positions.

T he air sack by being' made of india-rubber or similar tlexible and non-metallic man terial materially assists in improving the character oi the tone, that is to say, it mellows the otherwise metallic tone.

The invention is not limited to the construction ot air sack shown; said air sack may be a small bulb similar to the bulb (Z inserted in the tone arm passage and being a loose iit so that sound freely passes it, this bulb being increased in diameter from the hand bulb to throttle the passage and control the eti'ective size thereof in which case said inner bulb would have its position fixed within the tone arm.

Figs. T, 8 and 9 show how the inflation bulb fl may be arranged tor key operation to give a more sensitive control.

A box f is provided within whieh the power bulb d is located between a fixed seating g and keys 172-, which latter press against the bulbV at 7L.2 it'rom hand opera 'ion et their knob ends 7b3. Contact between the key and the bulb maybe by :t'airly hard india-rubber blocks. Two keys /zy are shown in the arrangement ot the drawings, either or both ot which can be hand operatedeither separately or together. The box may be a. part entirely separate from ,the instrument, or the primary Jfeatures ot it may torni part ot a special machine cabinet.

Having now described my invention what I claim and desire to secure by Letters Patent is l. A control device for sound reproducing instruments having a passage beyond the sound box, comprising an air sack o't elastic material, haying parallel walls one` of which is adapted to expand outwardly and the other inwardly, a hand operated bulb used outside the instrument `for intlating the air sack and a length of tube connecting the bulb with the air sack, the air sack bulb and tube being formed as a unit applicable to an instrument substantially as described.

Q. A control device for use with sound reproducing instrument having a tubular passage positioned beyond the sound box cornprising a tubular double walled air sack adapted to be disposed within the passage, a pneumatic bulb used outside the instrument for iniating the air sack, a length of tube connecting the bulb with the air sack and hand operated keys for controlling the sensitive operation ot the pneumatic bulb substantially as described.

3. A device to be used with sound reproduc-ing instruments having a tubular pas sage beyond the sound box, comprising a tubular sack adapted to he inserted into Ythe tubular passage, said sack consisting ot' outwardly and inwardly expandible coaxial tubular walls, a pneumatic bulb, and a flexible tube connectingsaid bulb and sack.

In testimony whereof I have hereunto set my hand in presence of a subscribing witness.

ARTHUR EMETT. Vitness:

Jol-IN P. FUERY. 

